Hi Dave.
Have you had the distributor out???
If so it may be out a couple of teeth.
To test this theory you must line up the two timing marks on the front of the motor on TDC (top dead centre).
When these marks are lined up, with the dizzy cap off.
The rotor button should be pointing to either plug one or,four and pointsshould be wide open at this point.
If it's not then remove the dizzy and rotate it around until it is pointing at either plug one or four.
If you wish to check which cylinder it's ready to fire on, remove the tappet cover, and the cylinder which is about to fire will have tappet clearance on both inlet and exhaust valves.
Once you have found this out, then your rotor will then have to be pointing to that spark plug, making sure that the points are in the wide open position.
Remembering it's only one or four that the motor will fire on.

when these two timing marks are in line.
hope this has helped you out.
bye for now.